The invention relates in general to the field of magnetoresistive read sensors and methods of fabrication thereof.
Magnetoresistive read sensors are known. FIG. 1 is a 2D cross-sectional view of a simplified representation of a prior art, current-perpendicular-to-plane (CPP) magnetoresistive read sensor 1′. This sensor 1′ comprises a stack of layers 11-15, which extend along a stacking direction z. An edge surface S of the stack (parallel to the stacking direction z) is further parallel to and forms at least part of a bearing surface S of the read sensor. The bearing surface is designed to face a recording medium, in operation. More specifically, this stack of layers includes:                A first contact layer 15;        A free layer 14, ferromagnetic, whose magnetic orientation varies according to an applied magnetic field, as known. The free layer is above the first contact layer 15;        A non-magnetic layer 13, above the ferromagnetic layer;        A spin injection layer 12, ferromagnetic, above the non-magnetic layer; and        A second contact layer 11 above the spin injection layer, such that a current can flow between the second contact layer 11 and the first contact layer 15 along the current-perpendicular-to-plane direction, i.e., parallel to the stacking direction z.        
Reducing the pitch between adjacent readers such as depicted in FIG. 1, e.g., in a multi-channel tape drive, is highly desirable in order to enable applications such as adjacent track recording and/or electronic servoing. To date, the minimum pitch achievable between adjacent read transducers has been limited due to fabrication challenges.
There is therefore a need for new designs and fabrication methods of magnetoresistive read sensors that overcome these fabrication challenges.